This core is a central morphology facility providing support for the investigators in the program project. The services provided include routine light microscopy processing, analysis of tissue sections, and special stains. In addition, where desired by the investigators, transmission electron microscopy (TEM), immunofluorescence, immunohistochemistry, and morphometric analysis services are available. Finally, this core provides digital image analysis and graphic illustration support for the investigators. In the past this core has received heavy usage and it is anticipated that demand will continue to increase. For example, during this past year over 2100 samples were processed for the sections of the program project. Of this total there were 1640 samples submitted for light microscopy analysis, 305 samples for immunohistochemistry and/or immunofluorescence studies and 181 samples for TEM. We anticipate that there will be heavy usage of this core by the investigators in the coming years. For example, in sections I, II, III, and IV light microscopy will be routinely used to monitor the intensity of the lung injury in various models. In addition, in vitro studies of isolated cells and tissue culture monolayers will be done in all sections using this technique. TEM studies will also be used extensively in this program project with all of the sections utilizing this technique. Morphometric analyses of tissue alterations utilizing primarily TEM will be done on selected tissues for sections II, III, and IV. Morphometric analysis is required to precisely quantitate injury to the lung with such parameters as percent alveolar and endothelial cell injury and quantitation of leukocytes and hemorrhage evaluated routinely by this method. In addition section II will use morphometry to evaluate the size and distribution of the granulomas in the lung. Frozen sections analysis of tissues and cells, particularly for immunohistochemistry studies, is heavily utilized currently by investigators and this will continue in the current proposal. Immunohistochemistry is the primary technique used for evaluating adhesion molecule and cytokine up-regulation in vivo and in vitro and will be utilized by all sections of the program project. Selected immunofluorescence studies will also be done utilizing frozen sections to evaluate immune complex induced lung injury and the effect of interventional studies primary in section 1. Finally, the core facility offers digital image analysis and graphic services including color digital laser printing for posters and publications for investigators in the program project.